An Orthodox student sexually assaulted a 17-year-old Austrian tourist during a heated game of spin the bottle.

Israeli-born Menachem Chaim Unger, 21, groped the girl at his friend's flat after being dared to go into a room alone with her during the game, Hendon Magistrates heard.

After a Shabbat dinner at the Golders Green Hillel House, Unger went to the house of a friend, Leonie Ettinger, to meet two Austrian girls. He had arranged for them to stay with Ms Ettinger in Golders Green.

He later played a sexually charged game of spin the bottle with the girls and two other friends. Players were asked about sexual experiences.

Unger's female friend went topless and played with a sex toy. One of the Austrian girls was told to remove her knickers and give them to him.

The victim, who said she had been uncomfortable with the game, said she was taken into another room where she was pinned her down and groped.

Unger told her: "You will regret it if you don't sleep with me," saying that every girl who came to stay with him did so because he could teach them things. But Unger told the court that nothing had happened in the room.

He was questioned about how he could wear a kippah and keep Shabbat - and still be sexually active.

He admitted sex before marriage was forbidden but said: "I am trying as hard as I can to be a good Jew; I believe God sees everything."

Katie Weiss, prosecuting, said: "You fancy yourself a bit of a stud and you were angry when she turned you down."

The victim contacted police nine days after the incident while staying with a friend, James Kay, in Oxford. Mr Kay said he had noticed that she had become "a changed person."

David Rosen, defending, said the girl had posted a sexually explicit New Year's greeting on her Facebook page. She and Unger remained Facebook friends for six months after he was charged.

But on Monday, Unger, a student at Middlesex University, was found guilty of sexual assault. He will be sentenced on February 7.